I recently wrote a piece at Law & Liberty on the Senate's power to expel Roy Moore in the event he wins the Alabama Senate special election. He has been accused of sexual misconduct, and calls for him to resign have not been heeded. Some have wondered about whether the Senate might refuse to seat him; I explain in the piece why that is inconsistent with the constitutional understanding set forth in Powell v. McCormack.

But what about the power to expel a member once seated? The Constitution says this:

Each House may determine the Rules of its Proceedings, punish its Members for disorderly Behavior, and, with the Concurrence of two-thirds, expel a Member.

I explain in the piece that there are few contours to the power to expel, except that it must occur by a two-thirds vote. That's mostly a procedural check, and the substance has largely been left to the Senate to flesh out. (Professor Brian Kalt shares similar thoughts in a Wall Street Journal opinion.)

I identify a couple of precedents that would limit the Senate's power to expel Mr. Moore. First, the Senate has typically wondered whether it has the power to expel members for conduct that arose prior to the candidate taking office. (Some earlier debates actually focused on whether it had to arise during that existing term in office and not from a preceding term, but recent Senate investigations have moved away from that view.) Second, the Senate has generally refused to expel a member for conduct known to the voters at the time of the election, the notion being that it's not for the Senate to expel a member with such baggange sent by the voters.

The Senate has not expelled a member since the Civil War, but it has investigated members who resigned before facing an expulsion vote, like Senator Bob Packwood in 1995.

New allegations have arise in recent weeks. Representative John Conyers and Senator Al Franken have been accused of sexual misconduct, and campaigns arose to urge their resignations.

Mr. Conyers heeded such calls this week and resigned, rather than face an ethics investigation and, perhaps, subsequent expulsion vote. His conduct arose during his terms in office (as he has been in the House for several decades).

Mr. Franken is facing new calls from a number of his fellow Senators to resign. Some allegations of his sexual misconduct arose from events prior to taking office, but certainly were not widely known to voters. He is also facing an ethics investigation.

It is worth noting how the rather underdefined precedents shaping Congress's practices under the Expulsion Clause may be experiencing a rather significant change right before our eyes. Ethics investigations and calls for resignation for (at least some) conduct arising prior to taking office suggest that a good number of Senators would apply the Clause in a way that the Senate has been reluctant to do in the past.

This is not to say that this is a wrong view, just to say that the Senate is, as is within its authority, deciding the proper scope of its authority under the Clause. It may be using informal means, like social media campaigns, political calls for resignations, and political party threats (perhaps offering primary challengers, withholding campaign funding, or revoking committee assignments), in ways that do not impact the Expulsion Clause.

But in the event Mr. Moore is seated, and the Senate begins to look at these recent precedents involving allegations of sexual misconduct prior to a candidate taking office, it may be moving toward a new understanding of its own power under the Clause.

That may not be the case, of course. Expulsion is an understandably extraordinary remedy, requiring significant consensus, and we have seen the Senate bluster recently and fail to carry through. These other tools at the disposal of the parties and the Senate may make the Senate reluctant to carry through with expulsion of Mr. Franken (if he does not resign in the next several hours) or Mr. Moore (if he is elected). But it is worth considering how recent weeks may be shaping, before our very eyes, a renewed attention to the Senate reconsidering its past practices and reinvigorating the Expulsion Clause.